Kristi has a mild mental disability. She is socially capable, but has the mental capacity of a 10-year-old.

Kristi was last seen by her family in Grand Forks, North Dakota on October 2, 1996. A family friend reported a brief sighting of her a couple of days later. On October 10, 1996, her father contacted local law enforcement authorities in Grand Forks to report her missing. An extensive investigation was conducted but her whereabouts remain unknown.

A former North Dakota man has been named a person of interest in Nikle's disappearance. He was convicted of kidnapping and shooting a mentally handicapped woman in Montana in 2003. The suspect is serving a 75-year prison sentence.